Method of degrading keratinaceous material and bacteria useful therefore

ABSTRACT

A method of degrading keratinaceous material is disclosed. The method comprises the steps of combining the keratinaceous material with Bacillus licheniformis to form a fermentation media and then fermenting the media for a time sufficient to degrade the material. The method can be used to produce amino acids from keratinaceous material and to produce a hydrolyzed feather product useful as a feed additive from the keratinaceous material. 
     A preferred keratinaceous material for carrying out the present invention is feather, and a preferred bacteria for carrying out the invention is Bacillus licheniformis PWD-1.

FIELD OF THE INVENTION

The present invention relates to fermentation processes generally, andparticularly relates to a process for hydrolyzing keratinaceous materialwith Bacillus licheniformis.

BACKGROUND OF THE INVENTION

Feathers are produced in large quantities by the poultry industry. Thesefeathers provide an inexpensive source of raw material for a variety ofpotential uses. Among other things, there has been considerable interestin developing methods of degrading feathers so they can be used as aninexpensive source of amino acids and digestible protein in animal feed.

Processes for converting feather into animal feed which have beendeveloped to date include both steam hydrolysis processes and combinedsteam hydrolysis and enzymatic processes. See, e.g., Papadopoulos, M.C., Animal Feed Science and Technology 16, 151 (1986); Papadopoulos, M.C. et al., Poultry Science 64, 1729 (1985); Alderibigde, A. O. and D.Church, J. Anim. Sci., 1198 (1983); Thomas and Beeson, J. Anim. Sci. 45,819 (1977); Morris and Balloun, Poultry Sci. 52, 858 (1973); Moran etal., Poultry Sci. 46, 456 (1967); Davis et al., Processing of poultryby-products and their utilization in feeds. Part I. USDA Util. Res. Rep.no. 3, Washington, DC (1961). Disadvantages of these procedures, such asthe degradation of heat sensitive amino acids by steam processes and therelatively low digestibility of the resulting products, have lead tocontinued interest in economical new feather degradation procedureswhich do not require a harsh steam treatment.

Accordingly, an object of the present invention is to provide a processfor hydrolyzing keratinaceous material which does not depend upon steamhydrolysis.

An additional object is to provide a process for convertingkeratinaceous material into amino acids at high yields of the aminoacids.

A further object of this invention is to provide a hydrolyzed featherproduct useful as a feed ingredient which is highly digestible andprovides a good quality source of dietary protein and amino acids.

A still further object of the present invention is to provide aneconomical animal feed which employs a hydrolyzed feather product as adietary amino acid source.

The foregoing and other objects and aspects of the present invention areexplained in detail in the Summary, Detailed Description, and Examplessections below.

SUMMARY OF THE INVENTION

A first aspect of the present invention is a method of degradingkeratinaceous material. The method comprises the steps of combiningkeratinaceous material with Bacillus licheniformis to form afermentation media, and then fermenting the media for a time sufficientto degrade the material. In addition to degrading keratinaceousmaterial, the method of the present invention can be used to produceamino acids. In this case, a fermentation media produced as describedabove is fermented for a time sufficient to produce free amino acidstherefrom, and the free amino acids are recovered from the media.

The method of the present invention can also be used to produce ahydrolyzed feather product. In this latter case, a fermentation mediaproduced as described above, with feather as the keratinaceous material,is fermented for a time sufficient to increase the digestibility of themedia (e.g., by enriching the concentration of digestible proteins andpeptides therein). Preferably, the bacteria in the media are then killedto form a hydrolyzed feather product useful as a feed ingredient (i.e.,the media with the bacteria are treated to kill the bacteria).

When the method of the present invention is used to produce free aminoacids or a hydrolyzed feather product, the fermentation step ispreferably an anaerobic fermentation step. Under anaerobic conditions,B. licheniformis does not actively grow. Hence, the utilization of aminoacids by B. licheniformis is decreased and free amino acid production,or enrichment, is increased. In addition, prior to the step of combiningthe feathers with B. licheniformis, B. licheniformis is preferably firstgrown under aerobic conditions (preferably in a liquid culture) toobtain enriched quantities of active bacteria. These procedures, asexplained in detail below, provide an efficient and cost-effective wayto degrade keratinaceous material and to utilize feather.

A second aspect of the present invention is a pure culture of thekeratinaceous material-degrading microorganism having the identifyingcharacteristics of Bacillus licheniformis PWD-1, ATCC No. 53757. B.licheniformis PWD-1 is the preferred microorganism for carrying out themethods described above.

A third aspect of the present invention is a hydrolyzed feather product,which may be produced by the method described above. This productcomprises partially hydrolyzed feather, proteins cleaved from thepartially hydrolyzed feather, and B. licheniformis cells (preferablycleaved from the partially killed B. licheniformis cells). Thishydrolyzed feather product may be combined with a carbohydrate sourceand, preferably, minerals and vitamins, to form an animal feed. Asecond, supplementary protein source may optionally be included in thefeed.

Additional aspects of the present invention are discussed below.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be carried out with all types of keratinaceousmaterial, including hair, hooves, and feather. Feather is preferred. Anytype of feather may be employed, including chicken, turkey, and duckfeather. Chicken feather is preferred, and is the material recited inthe text which follows. However, the teaching of this text is applicableto the degradation and utilization of all keratinaceous materials.

Prior to combining feather with B. licheniformis to form a fermentationmedium, the feather should be sterilized to kill bacteria naturallypresent on the feather which might otherwise disrupt the fermentationprocess. This sterilization step may be carried out by any means,including fumigation by contacting feather to formalin or ethylene oxidegas, by contacting feather to steam under pressure, or by combinationsof the same. We have found that, by contacting feather to steam underpressure, even for a time insufficient to sterilize the feather,subsequent bacterial degradation of the feather is substantiallyimproved. Accordingly, sterilization steps in the present inventionpreferably include a step of contacting the feather to steam for a timeand at a temperature sufficient to facilitate the subsequent bacterialhydrolysis thereof, even if this steam treatment step does notaccomplish a complete sterilization of the feather. We have found thatcontacting feather to steam under pressure, in an enclosed chamber, at125 degrees Centigrade for a time as brief as 2 minutes is sufficient tosubstantially enhance the subsequent fermentation hydrolysis thereof. Ifsterilization of feather is carried out solely by steam, the feathershould be contacted to steam under pressure at 125 degrees Centigradefor at least 15 minutes (a 15-20 minute treatment at this temperaturebeing, by definition, an autoclaving step). The time and temperature ofsteam treatment should be less than those employed in commercial steamhydrolysis processes, which employ treatment times of 35 minutes or moreat steam pressures of about 35 p.s.i. or more.

Prior to fermentation, B. licheniformis can be grown aerobically in anysuitable liquid growth medium (preferably a feather-based liquid growthmedium). The bacteria is preferably grown at a temperature of from about45 to about 55 degrees centigrade. After a sufficient quantity of thebacteria is grown (preferably about 10⁸ colony forming units permilliliter), the liquid growth medium is combined with feather in anysuitable fermentation vessel. Preferably, the liquid growth medium andfeather are combined at a high proportion of feather, so that thefermentation is a semi-solid fermentation. A preferred fermentationmedia comprises, by weight, at least about 1 part of dry feather per 4parts of liquid growth medium, or more preferably about 1 part of dryfeather per 2 parts of liquid growth medium.

Carbohydrate sources used to produce an animal feed according to thepresent invention include, for example, corn, oats, barley, sorghum, orcombinations of the same. These grains are preferably ground into a mealfor use in the animal feed. Supplementary protein sources include, forexample, soy meal, fish meal, blood meal, poultry by-product (groundpoultry offal), meat meal, and combinations of the same. An animal feedis comprised of from about 13% to about 25% by weight of protein fromall protein sources (both hydrolyzed feather and supplemental). Thehydrolyzed feather product may be the sole protein source, but ispreferably from about 2% to about 15% by weight of the feed. Othernutrients in small amounts, such as vitamins, minerals, antibiotics, andother substances or compounds may be included in the feed as required.

Bacillus licheniformis strain PWD-1 was deposited with the American TypeCulture Collection in accordance with the Budapest Treaty on March 23,1988, and has been assigned ATCC Accession No. 53757.

PWD-1 has been found to be a gram positive (but gram variable) bacteria.It is a straight rod-shaped bacteria, the rods being from about 2.1 toabout 3.0 microns long and from about 0.5 to about 1.0 microns wide,with the ends of the rods being rounded. Bacterial cells are found bothsingly and in chains. One subterminal endospore is formed per cell, theendospore being centrally located and cylindrical or oval in shape.

PWD-1 forms opaque, entire (mucoid) colonies which are erose andirregular in shape. Low convex, high convex (mucoid) and flat coloniesare seen. Colonies are seen to disassociate. The colonies are observedas glistening (mucoid) dull, dry, smooth (mucoid) and rough, with aninsoluable brown pigment present. Cells are motile (flagella beingpresent) and peritrichous.

PWD-1 grows at temperatures of from about 20° C. to about 55° C., withtrace growth being present at 60° C. In our hands, the bacteria isthermophilic, growing best at temperatures of from 45° C. to 50° C.Others have reported an optimum growth range of between 21 and 30degrees Centigrade. Experiments are under way to examine the effects ofdifferent growth media on optimum growth temperature.

PWD-1 produces acid, but not gas, from L-arabinose, D-xylose (weakly),D-glucose, lactose (weakly), sucrose, and D-mannitol. It can utilizeboth citrate and propionate as a carbon source. PWD-1 hydrolyzespolysaccharide, starch and casein, but not hippurate. PWD-1 liquifiesgelatin. It reduces, but does not reoxidize, methylene blue. It reducesnitrate to nitrite, but it does not reduce nitrite.

PWD-1 is voges Proskauer (5198) positive, voges Proskauer (5198 fil)positive, and voges Proskauer (5331) positive. It decomposes hydrogenperoxide but not tyrosine, is negative for indole, and is positive fordihydroxyacetone. PWD-1 is negative in the Litmus milk acid test,negative in the Litmus milk coagulation test, and negative in the Litmusmilk alkaline test, but is positive in both the litmus milkpeptonization and litmus milk reduction tests.

PWD-1 grows at a pH of 5.7 and at a pH of 6.0. It shows a pH VP5198 of8.0 or more. The optimum pH in nutrient broth is 7.0 to 7.5. It isaerobic and facultative. It does not grow in 0.02% azide. It generatesgas from sealed nitrate and grows in sealed glucose. It is negative forlecithinase.

A crude, cell-free extract comprised of a mixture of Bacilluslicheniformis PWD-1 proteins capable of degrading keratinaceous materialis also an aspect of the present invention. This crude extract isprepared, for example, by separating B. licheniformis PWD-1 cells fromtheir liquid growth media, the liquid growth media so becoming the crudecell-free extract. Alternatively, B. licheniformis PWD-1 cells may belysed (chemically or physically) in a liquid growth media to produce acrude, cell-free extract. Other means of preparing such an extract willbe apparent to persons skilled in the art. The crude, cell-free extractmay be provided in aqueous form. Alternatively, it may be provided inlyophylized form to increase the shelf life thereof.

A substantially pure, keratinaceous material-degrading, Bacilluslicheniformis PWD-1 enzyme is a further aspect of the present invention.This substantially pure enzyme is produced by separating the proteinswhich comprise the crude, cell-free extract described above into itsindividual, constituent proteins. Any suitable separation procedure maybe employed. Numerous such separation procedures, such as columnchromatography, are known to and routinely employed by persons skilledin the art for this purpose. The individual constituent proteins arethen screened for their ability to degrade keratinaceous material. Thatconstituent protein which best degrades keratinaceous material comprisesthe substantially pure enzyme. Like the crude cell-free extract, thesubstantially pure enzyme may be provided in either aqueous orlyophylized form.

Both the crude cell-free extract and the substantially pure enzyme, whenprovided in aqueous form, may be used to degrade keratinaceous material(preferably feather) by combining the same with the keratinaceousmaterial to form a fermentation media, and then fermenting thefermentation media for a time sufficient to degrade the feathers.

A still further aspect of the present invention is a DNA sequencecomprising a cloned gene or fragment thereof which codes for theproduction of a keratinaceous material-degrading B. licheniformis PWD-1enzyme or active fragment thereof. This cloned gene is produced asfollows. First, a multiplicity of B. licheniformis PWD-1 DNA sequencesare generated (as either a genomic DNA or complementary DNA library).These sequences are then inserted into DNA expression vectors to formrecombinant expression vectors. Next, the recombinant expression vectorsare inserted into suitable hosts to form transformants which express theDNA sequences. Finally, these transformants are screened for theproduction of a keratinaceous material-degrading enzyme. Transformantswhich express such an enzyme carry, as an insertion in the vectorcontained therein, the desired DNA sequence.

A multiplicity of B. licheniformis PWD-1 DNA sequences may be generatedby conventional techniques. One approach is to digest the genomic DNA ofan B. licheniformis PWD-1, with the ultimate goal being the preparationof a genomic DNA library. See generally R. 01d

S. Primrose, Principles of Gene Manipulation, 102-109 and (3d ed. 1985).Another approach is to isolate mRNA from B. licheniformis PWD-1 andgenerate cDNA sequences therefrom, with the ultimate goal being thepreparation of a cDNA library. See generally R. Old and S. Primrose,supra at 109-111; T. Maniatis, E. Fritsch and J. Sambrook, MolecularCloning: A Laboratory Manual, 187-246 (1982).

A variety of vector-host combinations may be employed to produce thecloned gene. Host cells may be either prokaryotic or eukaryotic cells,and, when the host cells are bacterial cells, they may be either gramnegative or gram positive bacteria. Useful hosts include, for example,Escherichia coli (including, for example, E. coli, X1776, E. coli X2282,E. coli HBlOl and E. coli MRCl), species of Salmonella (including, forexample, S. typhimurium, S. enteriditis, and S. dublin) species ofPseudomonas (including, for example, P. aeruginosa and P. putida), andBacillus subtilis.

Vectors used in practicing the present invention are selected to beoperable as cloning vectors or expression vectors in the selected hostcell. The vectors may, for example, be bacteriophage, plasmids, viruses,or hybrids thereof. Yectors useful in E. coli include plasmids (forexample, pSClOl, ColEl, RSF2124, pBR322, pBR324, pBR325, pAT153, pUC-6and pUC-8), bacteriophage lambda, cosmids, phasmids, and filamentouscoliphages. Salmonella species may be transformed, for example, withplasmids such as pJC217, pBRDOOl, and pBRD026. vectors useful in gramnegative bacteria generally include plasmids of incompatability groupsP, Q or W, which have broad host ranges (for example, Sa, RP4, andRSFlOlO), and Transposons such as TnT. Bacillus subtilis, a grampositive bacteria, can be transformed with S. aureus plasmids (forexample, pC194, pE194, pSA0501, pUBllO, and pT127).

Within each specific vector various sites may be selected for insertionof the isolated DNA sequence. These sites are usually designated by therestriction enzyme or endonuclease that cuts them. For example, inpBR322 the Pst I site is located in the gene for penicillinase betweenthe nucleotide triplets that code for amino acids 181 and 182 of thepenicillinase protein.

B. licheniformis PWD-1 DNA sequences may be inserted into the desiredvector by known techniques. If, however, the vector is to serve as anexpression vector, the vector should have a promoter, and the DNAsequence should be inserted in the vector downstream of the promoter andoperationally associated therewith. The vector should be selected so asto have a promoter operable in the host cell into which the vector is tobe inserted (that is, the promoter should be recognized by the RNApolymerase of the host cell). In addition, the vector should have aregion which codes for a ribosome binding site positioned between thepromoter and the site at which the DNA sequence is inserted so as to beoperatively associated with the B. licheniformis PWD-1 DNA sequence onceinserted (preferably, in correct translational reading frame therewith).The vector should be selected to provide a region which codes for aribosomal binding site recognized by the ribosomes of the host cell intowhich the vector is to be inserted. For example, if the host cell is tobe a prokaryotic cell such as E. coli, then the region which codes for aribosomal binding site may code for a Shine-Dalgarno sequence.

Transformants may be screened for the production of keratinaceousmaterial-degrading enzyme, or active fragment thereof, by any convenientprocedure. Preferably, the transformants are grown on an agar mediumcontaining powdered keratin substrate. Any powdered keratin may be used,but powdered feather is preferred, particularly powdered white feather,on which a clearing zone is easiest to observe. Colonies showing aclearing zone on the medium are producing the desired enzyme or enzymefragment.

The present invention is explained further in the following examples.These examples are provided for illustrative purposes only, and are notto be taken as limiting.

EXAMPLE 1 Comparison of Amino Acid Production By Aerobic and AnaerobicFermentations

Bacillus licheniformis PWD-1 was grown in batches of a sterile aqueousmedium containing feather as the sole source of carbon and energy. Eachliter of medium contained 0.5 grams of NH₄ Cl, 0.5 grams of NaCl, 0.3grams of K₂ HPO₄, 0.4 grams of KH₂ PO₄, 0.24 grams of MgCl₂.6H₂ O, 1.0grams of hammer-milled feather (a coarsely chopped feather) and 0.1grams of yeast extract. The media were adjusted to a pH of 7.5. Eachculture was incubated at 50 degrees Centigrade, one being grown underaerobic conditions and the other being grown under anaerobic conditions.The quantity of amino acids found in the media at day zero (prior toinoculation) and after five days of incubation under both aerobic andanerobic conditions, is shown in Table 1 below.

                  TABLE 1                                                         ______________________________________                                        Free amino acid concentrations in the growth                                  medium of feather degrading microorganisms                                    under aerobic and anaerobic conditions.                                                         Day 5                                                       Amino Acid (mg/l)                                                                          Day 0      Aerobic  Anaerobic                                    ______________________________________                                          ASP (N)    0.00       0.00     3.40                                         THR          0.78       0.90     9.00                                         SER          0.83       1.10     7.60                                           GLU (N)    0.00       1.70     11.80                                        GLY          1.61       0.50     6.60                                         ALA          1.35       1.10     14.50                                        CYS          0.11       3.00     10.20                                        VAL          0.36       2.10     17.10                                        MET          0.00       1.90     4.60                                         ILE          0.19       1.70     20.70                                        LEU          0.91       2.10     32.60                                        TYR          0.00       0.00     6.30                                         PHE          0.00       3.30     22.40                                        ORN          0.00       0.70     7.50                                         LYS          0.99       3.10     6.80                                         HIS          0.22       0.00     2.70                                         ARG          1.05       1.00     11.20                                        TOTAL        8.40       24.20    195.00                                       ______________________________________                                    

These data show that the total production of amino acids wasapproximately 800% greater under anaerobic conditions than under aerobicconditions.

EXAMPLE 2 Amino Acid Yields in Semi-Solid Fermentations

PWD-1 was grown in a liquid media like that described in Example 1(except that 10.0 grams of hammer milled feather per liter was usedinstead of 1.0 gram/liter) for 5 days at 50 degrees Centigrade underaerobic conditions to reach 10⁸ CFU per milliliter. An additionalquantity of hammer milled feathers was autoclaved with steam at 125degrees Centigrade (16 p.s.i.) for 15 minutes. The feathers were mixedwith the growth medium at a proportion of 250 grams feather per liter ofgrowth medium in a fermentation vessel to form a fermentation medium,and the fermentation medium was flushed with nitrogen. The fermentationmedium was then incubated anaerobically for five days at 50 degreesCentigrade with periodic agitation. The same procedure was carried outon a separate occasion, except that the fermentation step was carriedout aerobically. These procedures were duplicated for both conditions.The amino acid concentrations in the liquid phase of all thefermentation media were measured on day five of fermentation, these databeing given in Table 2 below.

                  TABLE 2                                                         ______________________________________                                        Total free amino acid concentrations (g/l) in                                 the liquid phase of the semi-solid phase                                      fermentations                                                                 Fermentation   Anaerobic Aerobic                                              ______________________________________                                        1              14.7      1.7                                                  2              12.4      1.9                                                  ______________________________________                                    

Note that, under anaerobic conditions, free amino acids are produced inquantities in excess of 10 grams/liter by semi-solid phasefermentations.

EXAMPLE 3 Production of a Hydrolyzed Feather Meal Food Product

After five days of anaerobic fermentation, a semi-solid fermentationmedium like that described in Example 2 above was autoclaved with steamat 125 degrees Centigrade for 15 minutes, then dried at 60 degreesCentigrade for 48 hours, and then milled through a one millimeter mesh.The resulting product was a brown powder comprises of partiallyhydrolyzed feather, short peptides, amino acids, and killed Bacilluslicheniformis bacterial cells. This product is useful, among otherthings, as a dietary source of protein for growing chickens, as shown inExample 4 below.

EXAMPLE 4 Animal Feeds Incorporating Bacillus Licheniformis HydrolyzedFeather

One hundred and twenty-eight chicks were divided into four equal groups,4×8 in each group. Each group was raised on a different diet: group (a)was raised on corn-soy feed 20% protein; group (b) was raised oncorn-soy feed/15% protein; group (c) was raised on corn-soy feed/15%protein plus 5% unhydrolyzed hammer-milled feather; group (d) was raisedon corn-soy feed/15% protein plus 5% protein from Bacillus licheniformishydrolyzed feather produced in accordance with the procedure describedin Example 3 above. All birds were weighted at three weeks of age andthe weights for each group averaged. These averages are shown in Table 3below.

                  TABLE 3                                                         ______________________________________                                        Ability of growing chickens to utilize feather-                               lysate as a dietary protein source.                                                               Mean Body Weight                                                              (grams)                                                   Diet                M ± SEM                                                ______________________________________                                        Standard corn-soy, 20% protein                                                                    554.7 ± 8.5                                            Standard corn-soy, 15% protein                                                                    503.9 ± 8.3                                            Corn-soy, 15% protein + 5% protein                                                                458.8 ± 7.1                                            from untreated feathers                                                       Corn-soy, 15% protein + 5% protein                                                                525.6 ± 8.9                                            from feather-lysate                                                           ______________________________________                                    

These data show that Bacillus licheniformis hydrolyzed feather can beused as an inexpensive source of dietary protein in animal feed.

The foregoing examples are provided to illustrate the present invention,and are not to be taken as restrictive thereof. The scope of theinvention is defined by the following claims, with equivalents of theclaims to be included therein.

That which is claimed is:
 1. A method of degrading keratinaceousmaterial, comprising the steps of combining keratinaceous material withBacillus licheniformis PWD-1 (PWD-1) to form a fermentation media, andthen fermenting the media for a time sufficient to degrade thekeratinaceous material.
 2. A method according to claim 1, furthercomprising the step of growing PWD-1 under aerobic conditions to produceactive cells prior to the step of combining the keratinaceous materialwith PWD-1.
 3. A method according to claim 1, wherein said fermentingstep is an anaerobic fermenting step.
 4. A method according to claim 1,wherein said fermentation media comprises, by weight, at least about 1part dry keratinaceous material per 4 parts of liquid culture of PWD-1,whereby said fermenting step is a semi-solid fermenting step.
 5. Amethod according to claim 1, further comprising the step of sterilizingthe keratinaceous material prior to said combining step to kill bacterianaturally present on the keratinaceous material which might otherwisedisrupt the fermentation process.
 6. A method according to claim 1,further comprising the step of contacting the keratinaceous material tosteam for a time and at a temperature sufficient to facilitate thesubsequent bacterial hydrolysis thereof, prior to said step of combiningthe keratinaceous material with PWD-1.
 7. A method according to claim 1,wherein said keratinaceous material is feather.
 8. A method of producingamino acids, comprising the steps of combining keratinaceous materialwith Bacillus licheniformis PWD-1 (PWD-1) to form a fermentation media,fermenting the fermentation media for a time sufficient to produce freeamino acids therefrom, and recovering the free amino acids from thefermentation media.
 9. A method according to claim 8, further comprisingthe step of growing PWD-1 under aerobic conditions to produce activecells prior to the step of combining the keratinaceous material withPWD-1.
 10. A method according to claim 8, wherein said fermenting stepis an anaerobic fermenting step.
 11. A method according to claim 8,further comprising the step of growing PWD-1 under aerobic conditions toproduce active cells prior to the step of combining the keratinaceousmaterial with PWD-1.
 12. A method according to claim 8, wherein saidfermentation media comprises at least about 1 part dry keratinaceousmaterial per 4 parts of liquid culture of PWD-1, whereby said fermentingstep is a semi-solid fermenting step.
 13. A method according to claim 8,further comprising the step of sterilizing the keratinaceous materialprior to said combining step to kill bacteria naturally present on thekeratinaceous material which might otherwise disrupt the fermentationprocess.
 14. A method according to claim 8, further comprising the stepof contacting the keratinaceous material to steam for a time and at atemperature sufficient to facilitate the subsequent bacterial hydrolysisthereof, prior to said step of combining the keratinaceous material withPWD-1.
 15. A method according to claim 8, wherein said keratinaceousmaterial is feather.
 16. A method of producing a hydrolyzed featherproduct useful as a feed ingredient, comprising the steps of combiningfeather with Bacillus licheniformis PWD-1 (PWD-1) to form a fermentationmedia, fermenting the fermentation media for a time sufficient toincrease the digestibility thereof, and then killing the bacteria in themedia to form a feed product.
 17. A method according to claim 16,further comprising the step of growing PWD-1 under aerobic conditions toproduce active cells prior to the step of combining the feather with thePWD-1.
 18. A method according to claim 16, wherein said fermenting stepis an anaerobic fermenting step.
 19. A method according to claim 16,wherein said fermentation media comprises, by weight, about 1 part dryfeather per 4 parts of liquid culture of PWD-1, whereby said fermentingstep is a semi-solid fermenting step.
 20. A method according to claim16, further comprising the step of sterilizing the keratinaceousmaterial prior to said combining step to kill bacteria naturally presenton the keratinaceous material which might otherwise disrupt thefermentation process.
 21. A method according to claim 16, furthercomprising the step of contacting the keratinaceous material to steamfor a time and at a temperature sufficient to facilitate the subsequentbacterial hydrolysis thereof, prior to said step of combining thekeratinaceous material with PWD-1.
 22. A method according to claim 16,wherein said keratinaceous material is feather.